Metal salts of alkyl beta-imino dipropionic acids



n 3,78,Z89 Ice Patented Feb. '19, 1563 3,;tt73,239 METAL SALTS F ALKYL BETA HrliiNQ DTPRUEIQNIQ ACHDS George P. Rowiand, .ln, Pottstown, and John J. Wolshi, Springfield, Pa, assignors to The Firestone Tire a Rubber Company, Altron, @hio, a corporation of (this: No Drawing. @riginal application May 12, 1959, er. No. 812,575, now Patent No. 2,996,4Q0, dated Aug. 15, 1961. Divided and this application Feb. 1%, 1961, Ser. No. 3333534 6 Claims. (El. Zed-429.7)

This invention relates to the suspension polymerization of vinyl chloride to yield resins having good dry plasticizer blending properties and good electrical propert ies, and also to certain novel metallic salts of alkyl betaimino dipropionic acid for use in said process.

Vinyl chloride resin compositions are generally made up by initially mixing the granular resin, liquid plasticizers, stabilizer, pigments, etc. in a ribbon or blade-type mixer until a uniform, granular, freeflowing blend results. The blend is then transferred to fusing and hot- Working machinery such as roll mills, banbury mills, extruders, calenders and the like for working up into the final desired resin products. It is highly desirable that a resin so processed shall have the property, during the initial mixing stage, of rapidly taking up the liquid plasticizer so that the resin appears macroscopically dry, the liquid plasticizer being completely absorbed into the pores of the resin granules. If this state is not achieved during the preiiminary mixing, considerable difficulties will be encountered in subsequent processing Any plasticizer not absorbed into the resin lubricates the granules so that they are not efiiciently homogenized in the hot-working machinery, which results in excessive power consumption and in fish-eyes and other discontinuities in the finished products. Very few resins on the market at present have good plasticizer absorption performance as above outlined.

Accordingly, it is an object of this invention to provide a novel process for the production of vinyl chloride resins having excellent plasticizer absorption characteristics.

Another object is to provide such a process in which use is made of the available suspension polymerization apparatus and techniques.

A further object is to provide new chemical compounds for use in the process above outlined.

SYNOPSIS OF THE INVENTION The above and other objects are secured, in accordance with this invention in a process in which vinyl chloride, or a mixture thereof with other unsaturated compounds copolymerizable therewith, is polymerized in aqueous suspension in the presence of certain bivalent metal salts of alkyl beta-imino dipropionic acids having the formula wherein:

alkyl represents an alkyl group of from 8 to 16 carbon atoms, and

Me represents a metal atom which may be barium, strontium, calcium, zinc or tin.

The resins so produced have excellent plasticizer-absorption properties.

THE ALKYL BETA-IMINO DI PROPIONIC ACID SALTS Referring to Formula 1 above, by far the preferred metallic component Me for these compounds is barium, followed by strontium, calcium, zinc and tin in decreasing order of preference. With respect to the radical alky the preferred and most convenient radical is the n-dodecyl radical, the alkyl beta-imino dipropionic acid corresponding to this value being conveniently available as lauryl beta-imino dipropionic acid, in which the lauryl groups are the mixed radicals containing principally dodecyl radicals but also some higher (e.g. tetradecyl) and lower (e.g. octyl and decyl) radicals, derived by the reduction of coconut oil fatty acids. The compounds are readily prepared by reacting, in aqueous solution, the sodium, ammonium, or other water-soluble salt (2) of an alkyl beta-imino dipropionic acid with a chloride or other water-soluble salt of barium, strontium, calcium, zinc or tin, the following reaction taking place:

CHrOHz-C 0 ON).

alkyl-N MeClg (2) GHECHPC'OONZ) ii CHzCHr-C-O Me 2Na0l The desired insoluble salt is recovered by filtration, centrifugation and the like. Specific exemplary compounds under Formula 1 above are barium dodecyl beta-imino dipropionate, strontium dodecyl bcta-imino dipropionate, calcium dodecyl beta-imino dipropionate, zinc dodecyl beta-imino dipropionate, stannous dodecyl beta-imino dipropionate, barium tetradecyl beta-imino dipropionate, barium decyl beta-imino dipropionate, barium Z-ethyl hexyl beta-imino dipropionate, strontium decyl betaimino dipropionate, stannous tetradecyl beta-imino dipropionate, and the like. It will be understood that mixtures of two or more compounds individually coming under Formula 1 are also contemplated, for instance, mixtures of compounds under the Formula 1 above in which the alkyl groups are derived from commercial mixtures of alkylating constituents, for instance the mixed alkyl radicals contained in the alcohols derived by the reduction of the mixtures of fatty acids occurring in natural glycerides such as coconut oil, the mixed radicals derived hy dimerization and trirncrization of propylene and butylene, oxo process alcohols and so on. Likewise mixtures of salts of different metals, for instance, mixtures of barium and strontium salts, may be used.

THE POLYMERIZATION In general, the process of this invention follows the ordinary suspension polymerization procedure, with the exception that the compound of Formula 1 is present. The suspension polymerization process consists in agitating the vinyl chloride monomer in an aqueous medium containing a non-micelle forrning protective colloid suspending agent. Suspending agents suitable for this purpose are hydrophilic high polymeric materials such as gelatin, starch, carragheen, albumen, agar-agar, gum tragacanth, polyvinyl alcohol, polyacrylic acid, polymaleic acid, methyl cellulose, and the like. The aqueous medium constitutes about at least half the entire polymerization mass. The reaction is promoted by the presence of free-radical-generating agents soluble in the monomer phase of the suspension, such as benzoyl peroxide, perbenzoic acid, lauroyl peroxide, p-chlorobenzoyl peroxide, t-butyl hydroperoxide, and the like. In the practice of the present invention, there will further be present a salt in accordance with Formula 1 above. The aqueous phase and the monomer phase are agitated together so as to suspend the latter in the former without, however, forming a permanent emulsion, and the temperature of the 6 mass adjusted to values such as to initiate the polymerization reaction, usually on the order of 30-100 C. The monomers in the suspended droplets become polymerized, yielding a suspension of granular resin in the aqueous medium. From this aqueous suspension the 10 resin is isolated by filtration. The amount of the Compound 1 used in the polymerization mass will generally be upwards of .05%, and preferably upwards of 1.0%, based on the weight of the monomers in the system. The upper limit for this concentration is not critical; as high as 10% could be added without adverse effect, so far as. the operativeness of the process is concerned. However, amounts in excess of 3% will usually be unnecessary and wasteful from an economic point of view.

It will be understood that the monomeric compositions polymerized according to this invention may be either unmixed vinyl chloride or mixtures thereof with minor proportions, say not over 20%, based on the weight of said mixtures, of one or more other ethylenically unsaturated compounds copolymerizable with vinyl chloride. Conversely stated, the mixtures should contain at least 80% vinyl chloride by weight. Ethylenically unsaturated compounds copolymerizable with vinyl chloride are exemplified in vinyl esters on the order of vinyl bromide, vinyl fluoride, vinyl acetate, vinyl chloroacetate, vinyl butyrate, other fatty acid vinyl esters, vinyl alkyl sulfonates and the like; vinyl ethers such as vinyl ethyl ether, vinyl isopropyl ether, vinyl chloroethyl ether and the like; cyclic unsaturated compounds such as styrene, the monoand poly-chlorostyrenes, coumarone, indenc, vinyl naphthalenes, vinyl pyridines, vinyl pyrrole and the like; acrylic acid and its derivatives such as ethyl acrylate, methyl methacrylate, ethyl methacrylate, ethyl chloroacrylate, acrylonitrile, methacrylonitrile, diethyl maleate, diethyl fumarate, and the like; vinylidene compounds on the order of vinylidene chloride, vinylidene bromide, vinylidene fluorochloride, and the like; allyl compounds such as allyl acetate, allyl chloride, allyl ethyl ether and the like; and conjugated and cross-conjugated ethylenically unsaturated compounds such as divinyl ketone and the like. For a fairly complete list of materials known to polymerize with vinyl chloride, reference may be had to Krczil Kurzes Handbuch der Polymerisations-Tech nik--II, Mehrstolf Polymerization, Edwards Bros. Inc., 1945, pp. 735447, the items under Vinyl chlorid.

THE RESINS PRODUCED IN ACCORDANCE WITH THIS INVENTION The resins produced in accordance with' this invention have the property of rapidly imbibing liquid plasticizers of all conventional types in the preliminary mechanical mixing. Microscopically examined, the resin granules will be found to be generally spherical, and of rather narrow distribution of particle diameters, usually on the order of 150-350 microns.

With the foregoing general discussion in mind, there are given herewith detailed specific examples of the practice of this invention.

The lauryl substituent is a mixture of alkyl radicals derived from the alcohols produced by the reduction of the mixed fatty acids of coconut oil; predominantly dodeeyl groups and tetradecyl groups.

A series of runs was made in accordance with the foregoing recipe, using each possible combination of amounts of gelatin and of barium lauryl beta-imino dipropionate in the several runs. In each run, the ingredients, other than vinyl chloride, were charged into a 12-ounce beverage bottle and mixed. The vinyl chloride, slightly in excess of the recipe amount, was next charged and allowed to vaporize to purge the free space in the bottle and to reduce the weight of vinyl chloride to the amount in the recipe. The bottle was then capped and tumbled in a water bath at 25 C. for one hour, after which it was tumbled in a water bath at 50 C. for 18 hours. At the end of this period, the bottle was vented and opened, and the polymer was separated from the suspension medium by filtration, washed on the filter with distilled water, and dried. The resultant polymer in every case had excellent plasticizer-absorbing properties, as observed on a microscope slide. This observation was made by placing a small quantity of the resin in a thin layer on a microscope slide, adding a drop of diocty! phthalate, and placing the slide on the microscope stage. The resin particles could be seen in the microscope to rapidly imbibe the dioctyl phthalate. The particle size and shape were very uniform, the particles being predominantly 280 microns in diameter and spherical, and the resin was free from fine and from coarse grains.

Example 11 VARIOUS METAL SALTS Calcium, strontium, stannous or zinc neutral salt of lauryl betaimino dipropionic acid 0.11 to 0.18

The lauryl substitnent is a mixture of aliryl radicals derived from the alcohols produced by the reduction of mixed fatty acids of coconut oil; predominantly dodecyl groups and tetradecyl groups.

A series of runs was made in accordance with the foregoing recipe, using the various salts of the imino acid in amounts over the range indicated. Each run was conducted in accordance with the procedure of Example I. Good resins from the standpoint of plasticizer-absorption were obtained in all cases. The optimum ranges for the amount of the salts used, together with the characteristics of the products, are tabulated herewith.

TABLE I Heat Sta- Optimum bllity (min- Amon Range in Description of utes, deter- Recipo Product mined) as in Example III Calcium 0.13O. 17 Shagg spheres 175;: 75

in diameter. Strontium 0.130.l7 Irregular spheres 310;: 65

in diameter. 0. 13-0-17 Irregular spheres 140 45 in diameter. 0.11-0. 17 d0 00 Example III LARGE SCALE RUN Pounds Vinyl chloride Water 200 Lauroyl peroxide 0.28 Gelatin (type B-100 Bloom) 0.50 Barium lauryl beta-imino dipropionate 1 0.20

The lauryl suhstituent is a mixture of alkyl radicals derived from the alcohols produced by the reduction of the mixed fatty acids of coconut oil; predominantly dodccyl groups and tctradccyl groups.

A. glass-lined steel autoclave provided with an anchor agitator and with a heating and cooling jacket was provided for the run. All ingredients except the water were charged first. The reactor was then closed, and the free space therein purged twice with vinyl chloride vapor followed by evacuation. The recipe amount of vinyl chloride was then charged, agitation commenced, and the temperature raised to 125 F., these conditions being maintained for 19 hours. At the end of this time the unreacted vinyl chloride was vented, and the reaction mass cooled to 25 C. and discharged. The polymerized vinyl chloride was recovered by filtration, washed on the filter with water, and dried. Following are the properties of the product.

Table II Relative viscosity (1% solution in cyclohexanone at 25 C.) 2.52.

Fisheye Rating 2 at 3 min.

Heat stability (peanut oil180 0). Failure in 75 min.

Bulking density (gms./cc.) 0.44.

Dry time 8 min.

Hot flow 3 min.

Screen analysis (percent retained): Percent mesh 0 40 mesh 0 60 mesh 0.4 80 mesh 1.0 100 mesh 92.0 140 mesh 3.6 200 mesh 1.8 325 mesh 0.2 Percent thru 325 mesh 1.0

The properties, other than conventional ones, tabulated above were determined as follows:

Heat stability: Grams Resin 100 Dioctyl phthalate 45 (Jo-precipitated barium-cadmium laurate 1 Dibutyltin dilauryl mercaptide 0.5

Fisheye rating:

Resin 100 Dioctyl phthalate 60 Dibutyltin dilauryl mercaptide 3 The above ingredients are milled together at 310 F. for 3 minutes, and then sheeted out as a film 13-17 mils in thickness. An 8-square inch specimen of the film is cut out, and the number of fisheyes counted and taken as an inverse measure of the rapidity with which the resin takes up the dioctyl phthalate plasticizer.

Day drier hot flow and dry time: Grams Resin 400 Dioctyl phthalate 200 Dibutyltin dilauryl mercaptide 12 A Day Mixer, which is a steam jacketed double-arm mixer with a capacity of 0.13 cubic feet with two tangential arms rotating at 36 and at 36 and 74 rpm. respectively, was employed in the test. Jacket temperature was adjusted to 330 F., but the temperature drifted downwardly during the test, so that the average temperature was about 210 F. The ingredients of the recipe were added cold to the hot mixer over a period of two minutes. Thereafter the progress of the mixing was watched, and the time at which the mixture fell free from the blades taken as the Hot Flow time. Likewise, small samples were removed at one-minute intervals and spread and pressed between sheets of paper in an unheated laboratory press under a pressure of 138 p.s.i. The length of time in the mixer required before a sample of the resin produced no stain on the paper was taken as the Dry Time, and is considered to be an inverse measure of desirable absorption behavior.

The salts of the lauryl beta-imino dipropionic acids used in the foregoing experiments were prepared as follows. I

Sodiumdauryl beta-imino dipropionate (Deriphat a product of Gen- A series of preparations was made in accordance with the above recipe, using the calcium, strontium, barium, stannous and zinc chlorides individually in the several runs. In each run, the ingredients at A were placed in a three-gallon crock provided with a propeller-type agitator, and agitated together until complete solution was achieved. The selected salt and water listed at B were made up into a solution, and slowly added to the solution of the ingredients A with continued stirring. A precipitate quickly formed, and the resultant slurry stirred for an additional five minutes after the last of the ingredients A had been added. The slurry was then filtered, and the recipitate thoroughly washed on the filter with water. The precipitate was then sucked as dry as possible on the filter. The precipitate was then dried in a circulating hotair oven at 200 F. for 24 hours. Substantially quantita tive yields were obtained in every case.

This application is a divisional application of our copending application Serial No. 812,575 filed May 12, 1959, now U.S. Patent 2,996,490.

What is claimed is:

1. A salt having the formula alkyl C H;- 0 Hrff- 0 in which formula alkyl represents an alkyl group of from 8 to 16 carbon atoms, and Me represents a metal selected from the group consisting of barium, strontium, calcium, tin and zinc.

2. A salt according to claim 1 wherein Me represents barium.

3. A salt according to claim 1 wherein Me represents strontium.

4. A salt according to claim 1 wherein Me represents calcium.

5. A salt according to claim 1 wherein Me represents tin.

6. A salt according to claim 1 wherein Me represents zinc.

References Cited in the file of this patent UNITED STATES PATENTS 2,686,798 Gmitter Aug. 17, 1954 2,872,468 Leistner et a1 Feb. 3, 1959 2,891,053 Meyer et a1. June 16, 1959 

1. A SALT HAVING THE FORMULA 